Many motor vehicles are equipped with braking systems to allow operators to control, slow or stop the vehicles when desired. A commonly used braking system is a disc brake system. In general, a disc brake system comprises a caliper assembly and a brake disc. The caliper assembly is secured to a vehicle knuckle or suspension component and the disc is connected to the wheel hub of the vehicle. The disc comprises an annular braking band. The caliper assembly comprises a caliper body which comprises two lateral walls disposed on both sides of the disc which are connected by means of connecting members which straddle the brake disc and further comprises a support structure in the caliper assembly. When the vehicle is in motion the disc passes between the two lateral walls of the caliper. At least two brake pads are housed in the caliper assembly inside of the lateral walls, which are on the disc side of the lateral walls, and disposed on each side of the disc. The brake pads comprise a body of a friction material and carrier plate typically a metal such as steel, having disposed thereon a material which creates friction when in contact with the disc. The brake pads are seated in close proximity or adjacent to abutments in the caliper assembly so as to hold them in place during operation of the vehicle. The brake pads are displaceable in a direction perpendicular to the plane of the brake disc. The brake pads can be acted upon by thrusting means such as a hydraulic cylinder or piston to place the friction material of the brake pads in contact with the disc which creates friction force between the pads and the disc to slow down and/or stop the vehicle.
Generally disc brakes have two sets of abutments on leading and trailing sides of the lateral wall of the support bracket disposed in the inside wall of the lateral wall of the caliper, to transfer the braking loads from pads. A major portion (tangential force component) of the braking force is reacted by the trailing side abutments for a given direction of rotor rotation. The support bracket of a given caliper assembly requires an outer tie bar to share the braking loads between leading and trailing sides of the support bracket and manage deflections. In some wheel packages, the available axial clearance between the wheel and rotor is limited and does not allow packaging of an outer tie bar on the caliper support. However, from the functional stiffness/stress aspect of the support bracket/caliper assembly design, an outer tie bar is required. A currently used design to eliminate the outer tie bar on the support bracket of the caliper assembly is to design the brake pad to have a pull-push or push-pull feature that will connect the leading and trailing sides of the support bracket and help share the braking loads. The trailing side abutment is referred to as push and the leading side abutment referred to as pull. A push pull being defined as a brake design that has push loading occurring before pull loading and vice versa. Hereafter, the terms pull push and push pull will be used interchangeably. A brake that is capable of push pull operation can also be made to function as pull push. There are push pull designs available that use anchor pins attached to the support as abutments and also support brackets machined with rails and pressure plate having mating features to achieve push pull function. See U.S. Pat. No. 7,201,258; U.S. Pat. No. 7,377,368; U.S. Pat. No. 5,957,245; US 2007/0240946; US 2007/0056812; and US 2005/0056496 all incorporated herein by reference.
Brake pads used in existing push pull designs generally require the use of high strength materials for the brake pad carrier plate, such as high strength steel which is difficult to process for conventional manufacturing processes such as stamping.
What are needed are caliper bodies, support brackets, caliper assemblies and disc brake systems which provide the advantages of push pull braking function, utilize standard steel for the carrier plate of the brake pads and allow the elimination of the outer tie bar on the outboard side of the brake system.